Specs and Photos of the Willys F-134 4-cylinder
One of the cars that put the roar in the Roaring 20's was John North Willys' 1926 Overland Whippet with its new 4-cylinder engine, which later became the basis of the "Go-Devil" engine used in the jeeps of World War II. The similar but taller "Hurricane" F-head engine, which Willys began putting in its larger vehicles in 1949, had the same 134 cu.in. (2.2 liter) displacement, but had its intake valves in the head rather than the engine block. The "F" is simply the shape of the up-and-down valve arrangement (150K JPEG).
The first 1/4-ton Jeep big enough for the new engine was the military M38A1 in 1951. The first civilian Universal Jeep with the Hurricane engine was the new "high-hood" 1953 CJ-3B. Seen here with an early F-134 is Willys-Overland chief engineer Delmar G. "Barney" Roos, who played an important role in the development of both the Hurricane and its predecessor the Go-Devil.
Maintenance Part Numbers
- Rotor cap: Prestolite IAT 1041
- Ignition points: Standard AL 4556P or #AL4556XP (the difference between P and XP is the quality.)
- Points: NAPA CS725A or CS709
- Condenser: NAPA AL 869 or AL 868 (with wire or with copper strap)
- Cap: NAPA AL70
- Rotor: NAPA AL69
- Fan belt: Dayco 22425.
- Oil Filter: Fram C-3P. Wix 51010 or NAPA 1010 or 1006 (1011 is same filter with 2 different size gaskets.) 1980's Mercedes-Benz diesels used the same filter.
- Sparkplugs: Autolite A7, AC Delco 45 or Champion J-8. Note: Current Autolite replacement number is 295. A current Champion 841 (J8C) is suitable. AC has discontinued the 45 plug but hardware stores in small towns may still have stock from the 70's. Modern resistor-type plugs don't perform well on older engines.
- 6-volt Battery: Auto-Lite 1M-100, 100 AmpHour (H 8 5/8" x W 7" x L 8 23/32")
- 12-volt Battery: Auto-Lite 11-HS, 50 AmpHour (H 9 7/32" x W 6 25/32" x L 10 15/64")
- Spark plug gap: 0.030 in. (0.762 mm)
- Spark plug torque: 25-33 lbs. ft. (34-44 Nm)
- Firing order: 1-3-4-2
- Distributor rotation: Counterclockwise
- Point gap: 0.020 in. (Prestolite)
- Dwell angle: 42 degrees
- Ignition timing: 5 degrees BTDC
- Bore and stroke :3 1/8 in. x 4 3/8 in. (79.37 mm x 111.12 mm)
- SAE Horsepower: 15.63
- Weight: 470 lbs. with fluids (Jeep Bible, Granville King)
- Max. Horsepower: 72 @ 4000 R.P.M. (71 @ 4000 R.P.M. on military M606s)
- Torque: 114 lbs. ft. (15.7 kg-m) @ 2000 R.P.M. (111 lbs. ft. @ 2200R.P.M. on military M606s)
- Compression pressure: 120-130 psi (8.4-9.2 kg-cm2)
- Compression ratio: 6.9:1 (7.4:1 high altitude option).
- Valves: 2-in. intake valves in head, exhaust valves in block.
- Valve clearances:
Intake: 0.018 in.
Exhaust: 0.016 in.
- Idle speed:
YF-938-SD carburetor: 600 rpm
YF-4002-S carburetor: 650-700 rpm
YF-4366-S, YF-4941-S, or YF-6115-S:
IAY-4401A distributor: 650-700 rpm
IAY-4401B distributor: 700-750 rpm
Surviving examples suggest the engines were painted black, often with an orange sealant coat underneath. Further information on paint is welcome.
Publications Including Further Specs
The F-134 engine number (beginning with the prefix 4J for original CJ-3B engines) is found on the water pump boss (20K GIF) on the front of the block. Letters following the engine number indicate odd-sized parts:
See Serial Numbers and Engine Numbers for engine numbers on surviving Jeeps of a specific model year, and Plotting Engine Numbers for more details on identifying original engines.
- A: 0.010" undersized main and connecting rod bearings
- B: 0.010" oversized cylinder bore
- AB: both of the above
- C: 0.002" undersized piston pin
- D: 0.010" undersized main bearing journals
- E: 0.010" undersized connecting rod bearing journals
Engine Photos on CJ3B.info
Here are direct links to some of the F-head photos on this website. For more information on a particular owner's Jeep below, use the Search page, or look on Jeep CJ-3B Owners and Photos. Thanks to Brian McCarthy for the two photos seen here.
See also Eric Lawson's photos of an F-head Engine Rebuild and Rus Curtis' photos of 1955 CJ-3B Details.
Illustrations in Willys Literature
Thanks to Wes K., Oldtime, Bruce Agan and all the photographers, including Jim Allen, Tom Edwards and Tony Phillipson.
See also my cartoon "Arrival of the F-heads". -- Derek Redmond
For more engine information on CJ3B.info, see F4-134 Engine Horsepower and Torque and lots of pages of Tech Tips including the F-head Engine Rebuild.
Elsewhere on the web, see Paul Niedermeyer's article Automotive History: The Curious F-Head Engine.
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Last updated 13 March 2017 by Derek Redmond firstname.lastname@example.org
All content not credited and previously copyright, is copyright Derek Redmond